errorNo 26 couldn't open file "mypass" with parameter starting with @

[sushicodeur]

I'm facing a strange behavior : I'm calling an API passing two parameters, when the _password starts with the char "@", ~/lib/Buzz/Client/Curl.php throws a RequestException (line 26)

errorNo : 26
errorMessage : couldn't open file "mypass"

$url = "http://project.dev/api/v2/auth/login_check?access_token=avalidtoken"
$headers = array();
$parameters = array(
        '_username' => 'me@project.com',
        '_password' => '@mypass',
    );

$response = $this->buzz->post($url, $headers, $parameters);

I occurs only when @ is placed in first position in the string.

Do I need to encode datas in some way ? I've tried to urlencode it, it removes the exception but my API doesn't receive the right data.